D. CHEMISTRY AND METALLURGY. 113 



From Lampyrus and the phosphorescence of dead fish it 

 can always be obtained in a state of less purity. The secre- 

 tion of this substance by the luminous animals higher in the 

 scale, such as Lampyrus and others, is, without doubt, up to 

 a certain point, under the influence of the nervous system, 

 this permitting them to shine at will. In this case the se- 

 cretion is arrested for the moment, but it is known that the 

 eggs of Lampyrus shine for some time after they are laid, 

 probably from containing a small quantity of noctilucine. 

 In the animals lower in the scale there appears to be the ex- 

 istence of a special organ for the production of light; and 

 where w r e find scarcely any traces of a nervous system the 

 secretion of luminous matter is often subject to external cir- 

 cumstances. 6 B, August 26, 1872, 547. 



SYNTHESIS OF AMMONIA. 



According to Chartier, if a current of electricity with- 

 out sparks be passed through a tube containing hydrogen 

 and nitrogen, a notable quantity of ammonia will immediate- 

 ly be formed. Hydrogen, similarly electrized, will decom- 

 pose fresh oxide of silver that has not become too old. In 

 the course of this combination, effected at the ordinary tem- 

 perature, the silver presents itself in small globules, which 

 imprison the oxygen, which is subsequently disengaged with 

 the formation of small lamellre of silver. 3 J5, August 22, 

 1872,698. 



CARBONIC ACID OF SEA-WATER. 



Mr. Lant Carpenter, who has been investigating the amount 

 of gaseous constituents in samples of deep sea-water obtained 

 during the Porcupine expedition of 1869-70, remarks that the 

 analyses show that both surface and bottom water contain 

 more carbonic acid and less oxygen in the more southern 

 than in the more northern latitudes. The examinations made 

 embraced samples taken from localities extending from the 

 Faroe Islands to Lisbon. Contrary to the general supposi- 

 tion, how r ever, he reports that there is no greater quantity 

 of dissolved caseous constituents in the bottom than in the 

 surface water, although he fully admits the power of press- 

 ure at great depths to retain gases in solution if once evolved 

 there. 1 A, August 23, 1872, 88. 



